1. Technical Field
This disclosure relates to a semiconductor integrated circuit (IC), and more particularly, to a high voltage generation circuit which generates a high voltage using a charge pumping method for a semiconductor IC.
2. Description of the Related Art
In general, semiconductor devices may require a voltage higher than a power voltage level supplied from an external source. For example, a flash memory device requires a high voltage in order to program or erase a memory cell. A circuit within the semiconductor device generating a voltage higher than an external voltage is referred to as a high voltage generation circuit or a boost circuit.
A charge pump circuit is usually used as the high voltage generation circuit. The charge pump circuit has one or more capacitors and generates a high voltage by pumping electric charges to the capacitors. A typical charge pump circuit is disabled when an output voltage reaches a predetermined target voltage. When disabled, the output voltage of the charge pump circuit is reset to a power voltage. The output voltage of the charge pump circuit is discharged to a power voltage level. As a result, the charges stored in the capacitors of the charge pump circuit are lost. Thus, when the charge pump circuit is enabled again, it takes time for the output voltage to replace the lost charges and reach the target voltage level, increasing the power consumption. As a result, there remains a need for a method to rapidly output a target voltage when a disabled charge pump circuit is enabled.